Contact device for induction apparatus.



No. 809,262. PATENTED JAN. 2, 1906. R. O. HOOD. OONTAG/T DEVICE FOR INDUCTION APPARATUS.

APPLICATION FILED APR. 11,1905.

wz'fflesses: Inventor.-

UNITED srnppsrnrnar caries.

RALPH HOOD, OF DANVERS, MASSACHUSETTS, ASSIGNUR OF @Nlll- -HALF TO WARREN 1).. KING, OF. PEABODY, MASSAGHUSETTS.

CONTACT DEVICE FOR INDUCTION APPARATUS.

Specification of Letters Patent. Application filed April. 11,1905. Serial 110- 254,921.

Patented Jan. 2, 1906.

To all whom it may concern:

Be it known that I, RALPH 0. H001), a citizen of the United States, residing at Danvers,

tion, reference being had therein to the ac-" companying drawings.

' and is especial My mvention is an improvement in inductionapparatus, particularly of that class which 1s used for the ignition of the explosive mixture in ex losion-engines and the like,

biles, where rehability of the sparking apparatus is very important.

My inventlon has for its object to produce a contact device for induction apparatus which shall be more durable and reliable than those heretofore used and the opera nection with the accompanying drawings,-

ereof are pointed and the novel features t out and clearly defined in theclaims at the close of this specification.

In the drawings, Figure 1 is a view, partly in section, of a device embodying my mvention, the wiring and certain other parts being indicated diagrammatically for convenience.

Fig. 2 is a view, somewhat enlarged, of the armature and connected parts.

Referring to the drawings, an'induction coil of ordinary construction is indicated at A. At its center is a core B, composed of a bundle of strips of soft iron. About this core B is placed the primary coil C, com osed of a 1 few turnsof coarse wlre, and outslde of the primary coil C is a secondary coil D, composed of a relatively large number of turns of relatively fine wire. In this secondary circuit is located the spark-plug or other sparking arrangement, which I have indicated by a cross E. In the primary circuit is placed .a battery F or other convenient and suitable source of electrical energy. There is also placed in this circuit a make-and-break deadapted for use in automovice of some convenient formas, for instance a commutator Gw lnch breaks the current of the primary clrcult at sultable 1ntervals, determined by the speed at which thatinstant ignition of the explosive material in the cylinder be produced. Accordingly I place in the primary circuit my improved contact devioe, which I will now de scribe.

At the end of the induction-coil A and opposite to the end of the core B, I support an armature H upon a convenient bent spring I, fastened to a rocking plate J on the top of the induction-coil A or in any other convenient situation upon the machine. By means of this rocking plate J, which is pivoted at K, and the two adjusting-screws L,I am enabled to regulate the tension of the spring I. The armature H is alternately attracted and repelled by the, core B under the influence of the breaks or fluctations in the current in the primary circuit, and these movements of the armature take place with great fre uency.

Supported by a convenient brac et upon the induction-coil A or the frame of the machine is an inclosing tube or casing 2, held in collars or end pieces 3 and 4. The casing or tube 2 is made from glass or other transparent material in order that the operator may readily see the condition of the parts within the said tube 2. The collars or end pieces 3 and 4 make air-tight joints with the tube 2, and I use shellac or some other suitable substance to insure that there shall be no leakage of air into the interior of the casing or tube of the contact-point 5, by means of whichthe contact-point may be rotated about its longitudinal axis and withdrawn or insertedfarther within the interior of the tube 2 for the purpose of ad'ustment. By this means I am enabled to a just very precisely the distance between the platinum tips 7 and 8 of the contact-points 5 and 6, which is a matter of considerable importance in the operation of a contact device of this kind.

The contactoint 6, attached to the armature H, passes t ough a closure or diaphragm 14, which closes the end of the tube 2, being securely held to the tube 2 by the collar or end piece 4. I make an air-tight joint .between the diaphragm 14 and the end piece 4 and tube 2 by the use of shellac or other convenient material, as before described.

On each side of the dia hragm 14 and about the stem of the movab e contact-point 6 I place a nut 15, by means of which a tight joint between the diaphragm 14 and the said movable contact-point is produced.

The closure or diaphragm 14 is made of thin sheet-rubber or other flexible and elastic material, so that it accommodates itself to the movements of the contactoint 6, these movements being very slight; ut it is obvious that the same result may be obtained by the use of a substantially inflexible closure, through which the contact-point 6 passes, so long as a substantially air-tight joint is made between the closure and the contact-point.

It will be seen from the foregoing description that the platinum tips 7 and 8 of the contact-points 5 and 6 are inclosed within a substantial, air-tight space, but are entirely visi ble to the operator from the outside. By this means the oxidation of the tips is greatly lessened and is made practically nothing, thus prolongin very materially the life of the ti s and great y increasing the reliability of t e ap aratus, since the oxygen in the air origina ly in the closure or chamber is very quickly consumed by the action of the sparks and is not replaced from the outer atmosphere, the amount of the oxygen in the air originally within the chamber not being sufficient to injure materially the points. The casing also serves to protect the contact-points from the weather and from dust.

In the practical operation of my device 1 do not find it necessary that the inclosure for the points be absolutely air-tight so long as the free passage of air to the interior is largely prevented. By the use of the rubber diaphragm or closure 14 I find that the contacta point 6, carried by the armature H, is given sufficient freedom of movement, but that the movement of the contact-point and its suportmg-armature is not perceptibly impeded iiy the diaphragm, while at the'same time afthem. I also find it very easy to replace the diaphragm 14 should it become worn or puncvtured.

What I claim is ratus, the combination of a casing, a flexi 1e closure therefor forming therewith a substantially air-ti ht chamber and contactoints, one of whic closure.

2. In a contact device for induction ap'pa-' passes through the said exible point, and a movable contact-point passing throu h the said flexible closure.

4. n a contact device for sparking ap aratus, the combination of a casing, a flexi 1e closure therefor forming therewith a substantially air-tight chamber, a movable contactpoint passing throu h the said flexible clo sure and operative y connected therewith whereby a substantially air tight joint between the said movable contact-point and the said closure is effected without impeding the movement of the said movable contactpoint.

5. In a contact device for sparking ap aratus, the combination of a casing, a flexi le closure therefor forming therewith a substantially air tight chamber, a fixed contactpoint, a movable contact point passing stantially air-tight chamber, a fixed contactmounted upon the said armature and passing IO point and a movable contact-point passing through the said flexible closure and forming through the said flexible closure. therewith a substantially air-tight joint.

8. In a device of the character specified, In testimony whereof I afiix my signature the combination with an induction-coil and a in presence of two witnesses. core therefor, of a contact device comprising RALPH O. HOOD. a casing, a flexible closure therefor, a fixed Witnesses: contact-point having an armature for the GEORGE P. DIKE,

said core and a movable contact point J. HENRY PARKER. 

